Pliers



March 3, 1953 .1. J. BANNISTER PLIERS 3 Sheets-Sheet 3 Filed May 6. 1952 r mm n JM @w nm f F/a/Z F/G. 2/ c ticularly to parallel jaw pliers.

Patented Mar. 3, 1953 UNITED STATES PATENT `OFFICE s PLIERS John J. Bannister, Newark, N. J. Application May 6, 1952, Serial No. 286,355

1 This invention relates to pliers, and more par- The object of my invention is to produce a simplified and improved form of parallel jaw pliers which will not jam and in which the jaws are always parallel to the length of the pliers and equidistant from their closed position.` It is characteristic of pliers made in accordance with my invention that there is a movable center block having angled, straight-line sliding contact with the adjacent ends of the jaws.

`This application is a continuation-impart of my copending application Ser. No. 683,381, iiled July 13, 1946 (now abandoned).

In the drawings:

Fig. 1 is a front elevation of a simple form of pliers made in accordance with my invention, the pliers being shown open.

Fig. 2 is a view similar to Fig. 1, showing the same pliers closed.

Fig. 3 is a side View of the pliers of Figs. 2 and 3. n

Figs. 4 and 5 are side and front views respectively, of one jaw of the pliers of Figs. 1, 2 and 3.

Figs. 6 and 7 are front and side views, respectively, of the center block oi the pliers of Figs. 1, 2 and 3.

Fig. 8 shows an isometric View of the jaw shown in Figs. 4 and 5.

Fig. 9 is a view in side elevation of the handles and disk of a preferred form of pliers made in accordance with my invention, the handles bedicating the point of application of pressure to close the pliers, and the `upper arrows the direction of the resulting pressure on the jaws.

Fig. 10 is a view in side elevation of the complete pliers of Fig. 9, the view including indication of the vertical positions of the block and disk relative to the main pivot of the pliers.

Fig. ll is a view similar to Fig. 10, with the pliers in closed position.

Fig. 12 is a View in elevation on an enlarged scale of the upper part of the pliers as shown in Fig. 11. s

Fig. 13 is a View similar to Figs. 10 and 11, with the pliers in semi-open position corresponding to Fig. 2.

Figs. 14 and 15 are side elevation and top plan views, respectively, of the centering disk of Figs. 9-13.

Figs. 16 and 17 are side and edge views, respectively, in elevation, of one of the jaws of the pliers of Figs. 9-13.

Figs. 18 and 19 are side and edge views, respec- 9 Claims. (Cl. fil-51.5)

. 2 tively, in elevation, of the'center block of the pliers of Figs. 9-13.

Fig. 20 is a side diagram of the block of Figs. 18 and 19, showing one of the cam rollers in contact with the block when the handles are in three positions-open, semi-open, and closed.

Fig. 21 is a diagram illustrating how the shape of cam portion 25 is determined so as to compensate properly for the straight-line sliding contact of both embodiments shown in the drawings.

Referring to Figs. 1-8, my pliers have the usual crossed handles l which, if desired, may be made of sheet material. The handles are hingedly connected at their crossings by a pivot pin 2. The forward or projecting ends 3 of the handles are connected at the jaw pivot pins 4 to opposed jaws 5. The jaws are recessed for this purpose. These pivot pins, of course, are intermediate the ends of the jaws and preferably near the midpoints of the jaws. It will be obvious" that closing the back ends of the handles will cause the jaw pivot pins to come together, close the pliers and apply pressure to any work in the jaws. This is the real source of movement of and pressure by the jaws, the parts hereinafter described being primarily for maintenance of parallelism, equality of position of the jaws, etc.

To keep the jaws parallel no matter whether the pliers are open or shut, and whether or not the jaws are in contact with any work in the pliers, I provide a center or cam block 6` having a slot 'f in the middle to receive the mainpivot pin 2 (see Figs. 6 and 7). As shown in Figs. 1 and 2, the pin has vertical, parallel, flat sides engaging the slot which has complemental flat sides (see Fig. 6). Thiscenter block can move lengthwise of the pliers to a limited extent by virtue of this flat-sided mounting'on the main pivot pin.

The movement of the block is transmitted to the jaws by virtue or an angled straight-line sliding contact between the block and each jaw. For this purpose the inner or back ends of the jaws 5 are formed with tenons 8 which interlock slidably in angularly arranged mortises l0 in the block 6. It will be noted that partly to prevent jamming of the parts, the tenons 8 andymortises I0 are in a straight or linear arrangement. They are at an angle to the longitudinal axis or vertical center line of the pliers, sloping up as they approach that line. It therefore follows that as the jaw pivot pins 4 approach each other and ythe pliers are closed, the jaws slide upwardly on the center block and toward the forward or working end of the pliers. The jaw pivot pins ,also are moving in this direction at this time, but not in the uniform manner given the tenons 8 by the mortises IIJ. The jaws are moving in an arc about the main pivot 2 of the pliers and therefore their horizontal component of movement is increasing and their vertical component decreasing. The sliding contact for the lower or inner ends of the jaws gives an unchanging vertical component and an unchanging horizontal cornponent. I use the movement of the cam block G to addto'or subtractrom the movement caused by thecammingsurfaca'i. e.. mortise Iton the upper edge of the block. It must be pointed out that the primary function of the block is to maintain the parallelism of the jaws, particularly when there is no work in the pliers. To keep the contact for parallelism, the lower `edge `cf Lthe block substantially opposite .the mortises is formed -into curved cam-shaped portions i2 which are engaged by rollers I3 mountedonpins I4 secured on the handles. It is these curved ...surfaces whichA give .the block its .name of fcam block. It will be noted that .there is 4a cam ...surface near each leg so .that the block `rises .evenly for the twojaws.

I.,will nowexplain, in connection-with the ern-z.

bodiment of Figs. 9-.21, how thesetwo vfactors, .the-slidingcontac-ts 8,v II)I and the camming. means ..I,3, A25,. merge to give ythe .necessary graduated .movement-equal to vthat of the arcuate movementof the jawpivot pins .4. r1`he movements VAgivenltotheztenons by the slidingin the mor- :tises'I-U-and the vertical. movement of the block equalthe movement of the jaws by the jaw pivot pins 4. Therefore, the jaws are kept parallel as itheyfarebrought together by the pins 4. Similarly, `in opening the pliers Vthe tenons 3 are .-moved outwardlyV and downwardly in the mortises I0 and' the center blockcamming means compensate toe-keep the jawsfoparallel.

"In the-embodiment of Figs. .9-21, I provide centering means'whichkeep the jaws equidistant at lall-times from the center line of the pliers, =fi.-^e.,the verticalline V9 lying lengthwise of the jawsand passing through the main pivot pin Iii.

" These means-alsofserve to keep the jaws parallel ftothat center line 9.

For these purposesI provide a washer' or disk .I-5 associated with the main pivot pin 2 see Figs. -Q-and 10). InFigs 14 and 15, I haveshownthe diskby itself. The disk is threaded on the main Y, pivot pin IB. and connected to .the two handles Il y,in-:thefollowing manner. .Axially off-center .on ftheidisk-at `diametrically oppositeV pointsY on one -iitsinta holei20 inthe-handle on 'thatside Befcause thehandleszat the holes 20 have small hori- :zontal components of Amovement while -the pins do not, ,the holes are made slightly larger horizontally than .the .pins. Since vthe disk is so mounted that it can onlymove vertically on the main pivot pin, the -.swivelled connections vtolthe .handles must-move vertically equally andY simulntaneously when the `pliers are being opened `or .closed This ensures that the-two jaws are equi.-

distant at all .times from the vertical or longiother.

.of the three situations exists.

I have shown the disk held against rotation by the following means. In the center block 2I on the side toward the disk I5 is a vertical groove 23 extending from the main pivot pin I6 to the bottom of the block. On the face of the disk toward the block is a key 24 adapted to fit in the lower end of the groove 23. Since the block cannot rotate on the main pivot pin because of the flattened sides, it follows that the disk also cannot rotate. It will be obviousthat the -disk could be'prevented from rotating byother means, if desired. If no disk is provided, it is sometimes :possible for the jaws to become cocked or tipped, though still parallel, if no work is in the pliers.

I will now discuss in more detail the obtaining :of the movement of the lower ends ci the jaws to match the movements of the jaw pivot points 4. AAssume-the jaws are in a, wide open position, asshown in Fig. l0, and are to be closed. The mortise IIJ in the left jaw of Figs. 10 et seq. will beconsidered. The straight line yof the mortise .cannotgive the correct path of motion. The camV block is used to compensate for this. VAThere are three possible situations. The totalmovement caused by the mortise orgui'de alone without movement may be too great, too little, or merely not properly distributed. Obviously it is the angle of the mortise which determines which In the drawings I have shown the last Situation where the total movementis correct. In the case of Figs. 1-8 the maximum opening of the jaws is about 35 but in Figs. 9-21 it is nearer 60. In these cases the vertical rise is not fast enough in the rst-part of closure. This is'the lpart Where the arc has a slope .greater than the slope of the mortises III. 'Iherefoiethe block is caused to rise. (Compare the elevations of the block as shown in Figs. 10 and 13.) In the angular Ymovement of the jaw pivotlocated in the last 45 before the vertical the rise is too rapid, so the block is lowered again. '(Compare Figs. 13 and 11.) In this part the pivot point 4 travels on a curve having a klesser vslope than the mortises I0. The cam lobes.25 ofthe embodiment of Figs. 9-21 are shaped to .accomplish this. They give additional vertical movement to the block when needed to compensate for the straight-line sliding contact. This makes the total movement correspond to the arcuate movement of the mid-points of the jaws. `In this way the horizontal components of movement are .equal to the horizontal components of Athe jaw pinmovements. Thisis shown in Figs. '20.and 2.1, where'three positions of the handles v.are shown .corresponding to Figs. 10, 13 and 11, respectively. vThe line .26 is the resultant ofthe .two factors of block Ymovement .and mortise sliding.

If the angle of the sliding surface of the mortise were lower, the block might rise throughout-the entire quadrant. If it were higher than in the example where .the -total vertical movement was correct, then theblockmight have to be lowered to compensate for the curvatureand for the total vertical difference.

In Fig. 20 I have shown the .main pivot pin I6 stationary and I have shown the cam lobes 25 and rollers I3 at the three elevations where By dropping vertical lines from the centers of circles C, B and A, I iind the vertical position which would be given at this point to the jaw by the mortise acting alone. These circles are on the arc oi movement of the jaw pivot pins li. The differences in length oi these vertical lines from C, B and A to the straight line 225 show the vertical compensation needed from the cam bloeit to leep the block in contact with the jaws as the latter are carried along by the jaw pivot pins 4l. I have drawn straight lines at these corrected distances and the points E, D, where these lines meet the verticale, correspond to the positions C, B, A of the jaw pivot pins. From these points is developed the curved line 2l resulting from the combination of the bloei; movement and the sliding of the tenons in the mortises. In Figs. and 21 the angle of the mortise is the same as in Figs. 1-11, 13 and 18. Since the movement of the block and the sliding oi the jaw on the block occur simultaneously, a straight- ,line contact is maintained between the jaws and the block.

In the embodiment of Figs. 9-21 I have shown in the block camming means, adjustment means to keep the relation of the block to the two jaws even. This consists of using eccentric studs I3 locked on the pins lil on the handles by the motion of the pins. This ensures the proper working relation and increases the safety of using the pliers. It might be noted that other means than the attened portion on the pivot pin, etc. could be provided to prevent rotation of the centering piece.

It may be noted here that any tendency oi the jaws to open when the pliers are in use is met by the reaction of the block and rollers and the handles instead of directly against the hand of the user. For example, consider when heavy pressure is encountered by the jaws in removing a tight nut. The outward force at the outer ends of the jaws due to their pivotal mounting causes a pressure on the unitary cam block which has a downward component. This is resisted by the rollers in contact with the camming surfaces on the block. In this way much of the resistance to closure which would otherwise be taken directly by the hands is offset in the pliers. It will be noticed that in addition to the opposing effect of the cam block and roller, there is opposition between the two jaws due to the angular surfaces of the block. The cam block also provides a more compact means of obtaining the parallel action than heretofore known. It should also be noted that the jaws are not only parallel to each other at all times but when using the preferred form of Figs. 9-21, they are equidistant from the longitudinal center line of the pliers and parallel thereto at all times.

What I claim is:

1. A pair of pliers comprising two jaws, a pair of crossed handles each pivotally attached to the forward end of one of the handles, and a pivot pinv hingedly connecting the handles at their crossing, in combination with a center block mounted on the pivot pin but movable lengthwise of the pliers and having angled straight-line sliding contacts with the ends of the jaws adjacent the block, and means controlled by the handles adjusting the movements of the block to the position of the pivotal attachment of the jaws to the handles so that the jaws are kept parallel.

2. A pair of pliers according to claim 1 in which the end ci each jaw adjacent the block is interlocked with the block in a siidable manner and the means for moving the block comprises cooperative camming means on the bloeit and handles.

3. A pair oi pliers according to claim 2 in which the cooperative camming ineens have eccentric adjustingr means to keep even the relation of the block to the two jaws.

e. A pair of pliers according to claim 1 in which the end of each jaw adjacent the block is slidabiy joined to the block along a straight line lying in the general direction oi movement of the pivotal attachment of that jaw to its handle whereby a freely sliding relationship between jaw and block is maintained, and the means for moving the block comprises curved surfaces on the block and cooperating rollers in the handles adapted to move the block lengthwise of the pliers at a varied rate such that as the pliers close, the end of each jaw attached to the block has the same horizontal component of movement at all times as the pivot point of the jaw.

5. A pair of pliers according to claim 1 in combination with a centering piece at the pivot pin of the pliers, said piece being pivotally connected to each of the handles at points on opposite sides of the pivot pin, and means preventing that piece rotating about the pivot pin but permitting movement of the piece longitudinally of the pliers, whereby the two jaws are kept equidistant from closed position.

6. A pair of pliers according to claim 5 in which the centering piece is a disk located adjacent at least one of the handles, and pins projecting laterally from the disk engaging the two handles, the pin openings in the handles being large enough to compensate for the horizontal component of movement of the handles.

7. A pair of pliers according to claim 5 in which there is in the means for preventing rotation of the centering piece, a iiattened portion on the pivot pin and a cooperating flattened surface on the centering piece.

8. A pair of pliers according to claim 7 in which there is a flattened .portion on the cam block engaging the flattened portion on the pivot pin, and a slide on the centering piece engaged by the iiattened portion of the cam block, whereby both the centering piece and the cam bloeit are prevented irom turning.

9. A pair of pliers according to claim 8 in which the centering piece is a disk located between one of the handles and the cam block, the two pins to the handles project from the handle side of the disk and the slide projects on the side toward the cam block.

JOHN J. BANNISTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 557,615 Schatz Apr. 7, 1896 '119,782 Furbish Feb. 3, 1903 2,063,532 Vertes Dec. 8, 1936 

